/Engine/Source/Runtime/Net/Core/Public/Net/Core/Misc/NetSubObjectRegistry.h
Adds a subobject and returns if it's a new entry or existing entry
[FSubObjectRegistry::EResult](API\Runtime\NetCore\Net\Core\Misc\FSubObjectRegistry\EResult) AddSubObjectUnique ( [UObject](API\Runtime\CoreUObject\UObject\UObject) * InSubObject, ELifetimeCondition InNetCondition )